Gisgraphy – open-source geocoder based on open data

https://www.gisgraphy.com/index.php

by pabs3 • 5 years ago

130 30 5 years ago

xs83• 5 years ago

This looks severely out of date, even with the best data sources this data gets stale very quickly unfortunately.

Reventlov• 5 years ago

I recently moved to Belgium (Wallonie) coming from France, and it's a nightmare with regards to addresses… Even google has trouble finding my home address, or it's off by a few hundred meters.

I can't stress enough that it should be one of the job of the state to do this or make this happen (e.g. in France we have https://fr.wikipedia.org/wiki/Base_adresse_nationale which, restrospectively, is probably why I never had any problem with addresses in France).

Uberphallus8• 5 years ago

France is just superior to every other country in regards to address data access, and anything geography really.

In the worst offenders, you have UK, where Royal Mail charges you for postcode data [0], or China where private mapping is simply illegal [1] and you have to go through some state-approved cash register (i.e. NavInfo).

[0] https://www.poweredbypaf.com/licence-our-products/licence-ag...

[1] https://en.wikipedia.org/wiki/Restrictions_on_geographic_dat...

Gys• 5 years ago

France is just superior to every other country in regards to address data access, and anything geography really.

That is a very bold statement? Do you have a source for that?

lucideer2• 5 years ago

In the worst offenders, you have UK, where Royal Mail charges you for postcode data

Actually, the UK is kind of a funny situation. A number of years ago the Ordnance Survey began publishing postcode data under a free (CC) licence. Royal Mail wasn't too happy, but as Royal Mail's APIs were a bit simpler and more direct (OS service was SPARQL-only) so I guess they didn't feel threatened enough to change their pricing. I worked for a company that had an account with Royal Mail at the time and I was tasked with parsing OS data.

That's many years ago and now that I revisit the OS offerings have changed. They appear to have relicensed, and split their offerings between a free db[0] without full addresses and a commercial db[1] with full addresses.

Either way, Royal Mail may have the established customer base but I wouldn't look to them exclusively to see who's "leading the way" in this space in the UK.

[0] https://ordnancesurvey.co.uk/business-government/products/op...

[1] https://ordnancesurvey.co.uk/business-government/products/ad...

laurensr• 5 years ago

In Flanders (for non-Belgians: the northern Dutch-speaking part of Belgium) there is CRAB ("Centraal Referentieadressenbestand" / "Central Reference Address File") which contains the lat./long. for every address in Flanders.

It can be accessed as a map layer at http://geopunt.be/ or as open data at https://overheid.vlaanderen.be/informatie-vlaanderen/product...

dhekir• 5 years ago

After moving to a newly-finished building, I realized most companies didn't have up-to-date databases and some forms prevented me from correcting the "mis-corrected" addresses. Missed a few deliveries during the first few months/years.

On the other hand, having lived in a country where such databases were notoriously unreliable, such automated processing didn't exist, so I didn't encounter that problem.

Sometimes, having something work "way too well" can lead people to believe it's perfect, and enforce it too strictly.

Uberphallus8• 5 years ago

I'm surprised I hadn't seen this project before.

I had been dabbling with the idea of a geocoding service that is highly accurate based on open data, but gave up because data quality is all over the place even for countries with excellent open data access (France being the gold standard in my book). I found that to have accurate geocoding I had to have an ETL stack that pulled data from 2-5 sources per country, with country-specific code for basically every country, and that's just to store usable data. Even keeping it to the major economic powers felt too daunting, nobody wants a partial coverage geocoder and I don't want to be a one man data janitor gig, which is what the whole thing felt like. And still large swaths of countries are totally uncoded for all sorts of reasons.

A quick search shows some of the problems I found in my quest, and some new.

1. Wrong postal codes for certain addresses, e.g. Place de Gaulle, Antibes, shows 06160 but it's 06600. It's probably taken from cadastre or nearest OSM tags, but it's wrong, different parts of the town have either of the postal codes. For France, the postal code relations/polygons from OSM are accurate, just don't take postcode info from anywhere else, really, unless for some reason your point falls within France but somehow out of any postal code polygons.

2. Missing addresses. For France, I did some analysis on open data to find what street names were the most common, and found ~15k steets/squares/etc named "de l'Église", due to basically every town having at least a church and naming their street/square after them. Not sure if a problem with the data or with the parsing, but it only shows a few dozen.

3. While OpenAddresses is doing an amazing job, I only found the coordinate data to be accurate, and not always. Most of the fields in their own JSON are empty (postcode, district, region, and sometimes even city), but Gisgraphy takes them at face value, e.g. first result for Улица Деревянко is just that, it only shows street name. Also the coordinates are broken: 0.140642,34.6784995 falls either in Kenya or Algeria (coordinate swap is also rampant in many sources, which is a another topic). That is the official data from Kharkiv, Ukraine, which probably geocodes the locations in a different system than WSG84 for, you know, reasons. OA tends to focus on easy to process data, and can't blame them, since the state of the whole geocoding world is an absolute clusterfuck.

4. Related to 3, OpenAddresses only has (had?) two towns from all of Ukraine (Kharkiv and Dnipro) with really terrible data. But OSM data is also fed to their model, so data overlaps, sometimes with different scripts, or languages. So the street above, "Улица Деревянко", which is in Russian btw, appears again as "Дерев’янка вулиця" which is Ukrainian. The whole l10n/i18n part of geocoding is another tough problem to solve, because letters written to Derevyanka Vulitsa will arrive as well, transliteration data is spotty at best, but for many languages it can be transliterated through software, again, depending on many factors.

That said, I'd love to work on a project like this as part of a team.

timita• 5 years ago

The guys at OpenCage Geocoder[0] are doing a great job using only open data. But they are a team with over a decade of experience parsing an deduplicating address data from dozens of countries.

That said, their jobs page doesn't have much for now, but you may want to keep an eye on it.

Disclaimer: the founder of the company and I are acquaintances, but my assessment is only based on the quality of their service. I've been using it in production for reverse geocoding for a few years now.

[0] https://opencagedata.com/

freyfogle3• 5 years ago

Hi,

Ed from OpenCage here, thanks for the kinds words! It's true we don't have any open positions right now. But anyone who is into geo stuff in general and geocoding specifically can dive in to OpenStreetMap and the open source libraries we (and many others) rely on and contribute to. Most notably Nominatim https://nominatim.org

Here's a podcast interview I did last summer with Sarah Hoffmann, the lead maintainer. https://thegeomob.com/podcast/episode-35

wenbert• 5 years ago

I've had a pet projects that involved a lot of geo-things. I've tried heaps of ways to do it but nothing comes close to Google unfortunately. Especially in non-USA addresses.

Are paid options any better? Like the one from Arcgis? Or is google still more accurate?

Uberphallus8• 5 years ago

Depends on the scope of your project, but for address data the best I found is Loqate[0], which is IMO very expensive but also very good. I'd only target their API if I'm making/saving money in the process, which kinda limits its use for toy projects. Google's accuracy varies wildly, and in most regions I find OSM Nominatim better.

[0] https://www.loqate.com/

dagw• 5 years ago

in most regions I find OSM Nominatim better.

What regions? I work in GIS and have tried Nominatim in several projects, and it always ends up being so error prone we have to abandon it.

AdamTSaunders• 5 years ago

I've found the here.com (https://developer.here.com/documentation/geocoder/dev_guide/...) geocoder to be close to the quality of Google's, with nicer pricing model - a good amount of free geocodes before you start paying.

tomjuggler• 5 years ago

If this works it will be really useful. You know how much Google charges for reverse geocoding these days!

adonese• 5 years ago

I was literally one hour ago talking to my previous professor and supervisor regarding a reverse geocoding solution that targets local consumers!

xiekomb• 5 years ago

There is also Pelias which is a very good open source geocoder: https://pelias.io

Gisgraphy – open-source geocoder based on open data

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